Originally Posted by Swim team capt.
When your hull i in the water your body weight makes the bottom sag alittle, not be forced up by water pressure, I did do a little study on this using a dive mask in a swimming pool and you would be supprised at how much oil canning goes away when you are in your boat in the water.
If you are worried about oilcanning don't seal launch, splat or boof rocks.
Or for that matter don't paddle it at all. Oilcanning generally happens under the seat and can be solved with some foam under the seat. I've seen enough people edge their boat or roll and show major oilcanning present to not really buy that the oilcan pops out as soon as you jump in your boat, unless, it keeps popping in and out as you roll and edge your boat - hard to imagine. However, it's a very different problem than cranking the shit of your boat on a rack and driving around with major depressions in your plastic. That can't be good for your boat.
Anyway, thanks for all the responses. The only conclusion I've really been able to make is that there are lot of superstitious boaters who are unwilling to ever orient their boat upside down. I read some study recently saying that people in more unstable, unpredictable careers tend to be more superstitous than their counterparts (also extended to cultures that are say dependent on weather for the food supply). I guess it makes sense that kayaking breeds superstition.
For now I think I'm going to tie 'er down the same as I always have, but I'll still probably be cringing as I drive over a mountain pass in the June afternoon sun wondering how many days I just cost my hull.